(a) Field of Invention
The present invention relates to polyfoam coolers and more particularly to a portable cooler for transporting and cooling canned or bottled beverages.
(b) Description of Prior Art
There exists a variety of coolers on the market intended for the purpose of carrying canned or bottled beverages, some of which provide a cold pack as part of the package. These cold packs are supplied as soft packs or hard shell containers filled with the so-called "artificial ice", which is a very viscid, non-toxic chemical (carboxyl) having a lower freezing temperature than ordinary ice (25.degree. F. or less).
The polyfoam coolers are generally box-shaped with body and lid, and such cold packs are intended to be placed upon pre-chilled beverages placed in the cooler. In other known designs, the cold pack is releasably attached to the cooler lid itself. Such an arrangement is moderately successful in keeping the beverages cool for a period of time. However, such arrangements are not successful in keeping the beverages cold for a prolonged period of time, such as eight hours or more, for the simple reason that the heat-absorption capability of the cold pack, in b.t.u.'s/hour, is invariably lower than the heat input to the cooler from the ambient air, in b.t.u.'s/hour, therefore the temperature of the beverages continues to rise from the outset, 2 degrees F. per hour being not uncommon. This deficiency, however, is not normally because the quantity of artificial ice provided is inadequate to the purpose, but rather the heat-absorption area of the cold pack is inadequate to the purpose. This fact is borne out by the observation that, in practically all cases of cooler use, it is found that there is still unmelted ice left in cold packs after the contents of such coolers have been consumed, and such contents (beverages) have been consumed at much higher temperatures than that at which they were when placed in the cooler.
One solution to the problem would seem to be the provision of larger, bigger quantity, cold packs to develop larger areas of heat absorption. This solution, however, would result in higher costs and even more ice being unused at the end of the consumption period.
A much more practical and desirable solution resides in the re-design of the cold pack to more fully develop its heat absorption capability to such an extent that the beverages in the cooler may be chilled to their initial temperature at any time and over a prolonged period of time, such as 24 hours.